[alexisq]

Dear OpenFOAM community,

I'm trying to simulate a spring-loaded pressure relief valve. Something like that [URL="https://www.youtube.com/watch?v=O_19cmEO6gI"] but I have several problems.

1) First, I tried to simulate without any piston or spring, just the body of the valve. It's an inlet/outlet type of pipe. I set the mass flow rate at the inlet and the pressure at the outlet. I used interFOAM. The thing is that the pressure, where there is still 100% air, is equal to the high pressure of the fluid and not atmospheric. The same happens for the velocity that is not zero at all at the outlet even though there is no flow yet.

--> How to have a real behaviour of the pressure and velocity fields in the valve for both liquid and air? Is there a way to separate both liquid and air velocity and pressure properties ?

2) Secondly, I included the piston (without spring) inside the geometry to see if the liquid pushes it back. I used both RigidBodyMotion and 6DOFRigidBodyMotion but can't find a way out. It crashes when the fluid is getting closer to the piston.

--> How to properly set the file to include the motion of the piston ? What about the fvSchemes and fvSolution ?

3) Finally, I included the spring via a linearSpring constraint. To include the piston, I set a few cells from the walls to avoid topology problem. But, the spring, as expected,pushes the piston in the fully closed position. At the end, it touches the walls meaning the cells of both piston and wall overlap and it crashes. The same problem can be found when the piston hits the wall when fully opened. The one that prevents the piston to "escape".

--> How to deal with the interaction with the walls or is there a way to limit the range of translation of the piston ?

Thanks in advance,

Alexis